Cooling arrangement for drum dryer fan bearings



pri l1, 1967 G. D. FLAITH ETAL 3,313,039

COOLING ARRANGEMENT FOR DRUM DRYER FAN BEARINGS 2 Sheets-Sheet l Filed April 26,' 1965 INVNToRsr GEORGE DONALD FLAITH GEORGE ROBERT HOWARD April l1, 1957 G. D. FLAITH x-:TAL

COOLING ARRANGEMENT FOR DRUM DRYER FAN BEARINGS 2 Sheets-Sheet 2 Filed April 26, 1965 INVENToRs: GEORGE DONALD FLAITH GEORGE ROBERT HOWARD ATVTYS.

United States Patent O 3,313,039 COOLING ARRANGEMENT FUR DRUM DRYER FAN BEARINGS George Donald Flaith, Wyndmoor, and George Robert Howard, Philadelphia, Pa., assignors to Proctor & Schwartz, Inc., Philadelphia, Pa., a corporation of Pennsylvania Filed Apr. 26, 1965, Ser. No. 450,719 16 Claims. (Cl. 34-115) The present invention relates generally to the cooling of drum dryer fan bearings and relates more particularly to an arrangement for cooling the bearings and drive belt of an axial fan mounted within a dryer drum.

`In certain types of modern drum dryers, axial fans are mounted internally of the dryer drums for circulating the drying air through the drums. This type of fan arrangement minimizes iloor space requirements and has a high evaporative capacity. However, since drying air temperatures are commonly in excess of 400 F., and since presently available lubricants generally cannot provide adequate lubrication at temperatures above 300 F., the fan bearings are subject to destructive wear and must be frequently replaced.

Although the fan motors are usually located outside of the drying chamber and are operatively connected to the fans by belt drives, the fan belts are exposed to the destructive heat conditions and similarly require frequent replacement.

In view of the above problems, it is a primary object of the present invention to provide an arrangement for cooling the bearings of an axial fan mounted within a drum of a drum type dryer.

A further object of the invention is to provide a cooling arrangement as described which includes means for cooling the drive belt connecting the fan with a fan motor mounted externally of the drying chamber.

Additional objects and advantages of the invention wil-l be more readily apparent from a consideration of the following detailed description of embodiments thereof when taken together with the accompanying drawings wherein:

FIG. 1 is a side elevational view showing schematically a drum dryer embodying a fan bearing cooling arrangement lin accordance with the present invention;

FIG. 2 is a sectional view taken along line 2 2 of FIG. l showing the interior components of the dryer in detail;

F'IG. 3 is a sectional view through a dryer fan taken along -line 3 3 of FIG. 2;

FIG. 4 is a fragmentary view taken along lineV4-4 of FIG. 3;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 3;

FIG. 6 is a plan view of the fan vassembly shown in FIG. 5, partly cut away to illustrate the iiow of cooling air therethrough;

FIG. 7 is a sectional view of a modified cooling arrangement for a dryer fan; and

FIG. 8 is a partial side rview of the apparatus shown in FIG. 7.

lReferring to the drawings, a drum dryer 16 embodying the present invention is shown in FIGS. l and 2 and includes a housing 12 enclosing a `drying chamber 14. Rotatably mounted within the drying chamber 14 upon rollers 16 are a pair of perforated dryer drums 18 and 20. The Adryer drums are driven in rotation by a variable speed motor drive 22 coupled to a gear reducer 24 which drives each drum by means of a roller chain 26 engaged with a peripheral sprocket 28 on the drum.

Fan assemblies 39 and 32 are respectively Vmounted within the drums 18 and 20 to provide an upward circu- 3,3l339 Patented Apr. 1l, 1957 lation of air through the drum 118 and a downward air flow through the `drum 20 as indicated in FIG. l. Wire mesh lint screens 3-4 and 36 positioned respectively beneath the fan assembly 30 and above the fan assembly 32 filter the circulated air before it is drawn through the fans. Gas burners 38 and 40 within the drums are respectively positioned above the fan assembly 30 and below the fan assembly 32 to heat the air circulated through the drying chamber. Instead of gas burners, however, steam or electric heating units may be used.

lDrum dryers are used for drying various types of materials such as cloth, bers, veneer, etc. The material 42 to be dried, in this case for example cloth, is introduced to the dryer on the infeed conveyor 44 from which it passes onto the drum 18, traveling around the lower half of the drum and being maintained against the perforated surface thereof by the drying air owing upwardly through the drum. The material is transferred to the second dum 20 and is similarly maintained against the drum surface by the drying air flow passing downwardly through the drum. The dried material moves from the drum 29 onto the delivery conveyor 46 on which it is cooled by passage beneath the nozzle box 48 through which cooled air is directed by the nozzles S0 onto the material. An adjustable folder 52 is provided at the end of the devilery conveyor to fold the dried cloth.

As shown in FIGS. 2-6, the fan assembly 30, which is identical to the fan assembly 32 although reversed in direction, includes an axial fan 54 which is mounted on an open ended horizonal duct 56 extending within the drum 18 between the side walls of the housing 12. Air is funneled into the fan through the concentric inlet cone 58 mounted on the transverse supports 60.

The fan 54 includes a cylindrical inner fan housing 62 downwardly depending from the duct 56. Concentrieally mounted within the inner housing 62 is the fan drive shaft 64 journaled by the upper bearing 66 in the duct 56 and the lower bearing 68 on the bearing support '70 within the inner housing 62. A fan hub 72 is keyed to the lower end of the fan driveshaft 64. The hub includes a rounded dome portion 74 and extends upwardly in a cylindrical portion 76 concentric with and spaced from the inner housing 62. The fan blades 78 extend radially from the cylindrical portion 76 of the hub. A cylindrical Cowling Sil of the same diameter as the cylindrical portion 76 of the fan hub is secured to the duct S6 in spaced concentric relation to the inner housing 62 and closely adjoins the fan hub at its lower edge.

The fan is operatively connected to a fan motor 82 on the exterior wall of the dryer housing 12 by a belt drive which passes through the duct 56. The belt drive includes a belt 84 enga-ging a drive sheave 86 on the fan motor shaft and a driven sheave 88 secured to the upper end of the fan drive shaft 64.

The duct 56 is divided into an inlet duct 89 and outlet duct 90 by the curved wall 91 which is a continuation of one half of the inner housing 62. The inlet duct extends over the inner housing and ports 92 in the duct floor allow air to flow from the duct into the inner housing. Similar ports 93 in the bearing support 7l) permit a downward air flow through the open lower end of the inner housing. An impeller 94 mounted on the shaft 64 between the lower end of the inner housing 62 and the fan hub 72 acts to centrifugally impel air radially against the dome portion 74 of the hub along which it passes upwardly into the annular passage 96 between the inner housing 62 and the spaced hub cylindrical portion 76 and cowling 80. Slots 9S in the walls of the outlet duct 9@ along with the opening 100 in the oor of the duct connect the passage 96 with the outlet duct.

During operation of the fan, the impeller 94 circulates a ow of cooling air through the fan assembly, the air being drawn into the cooling duct, through the inner housing into the impeller and thence driven into the passage 96 and out through the outlet duct 90. Both the belt 84 and the bearings 66 and 68 are cooled by the flow of cooling air to a reasonable operating `temperature well below the drying air temperature.

` A modified embodim-ent of the invention is shown in FIGS. 7 and 8 wherein the outlet duct is eliminated, the airflow through the passage 96 passing through an annular slot 102 between the cowling 86 and the hub cylindrical portion 76 into the drying chamber. The construction and operation of this embodiment is in other respects the same as that described above. This arrangement provides the advantages of introducing fresh air into the dryer andeliminating a flow of hot air into the dryer room. The fan should preferably be designed so that the slot 102 is on the suction side of the -fan to provide the most effective cooling air circulation.

Manifestly, changes in details of construction can be effected by those skilled in the art without departing lfrom the spirit and the scope of the invention as defined in and limited solely by lthe appended claims.

We claim:

1. In a drum type dryer including a housingenclosing a drying chamber, a perforated drum rotatably disposed within the drying chamber, an axial fan mounted within the drum for circulation of air therethrough, said fan including a drive shaft, bearings supporting said drive shaft, and a hub secured to an end of said drive shaft having fan blades extending radially therefrom, means for driving said fan in rotation, and means for heating the air circulated within the drying chamber, the irnprovement for cooling the bearings of the fan comprising means within the drying chamber enclosing the fan bearings, said latter means including an inner housing, and duct means opening outside the dryer housing connected with said inner housing, an impeller on the drive shaft between said inner housing and the hub, said hub extending in spaced relation around part of said inner housing to form a passage therebetween, and means for venting said passage, said impeller being adapted during rotation of the fan to draw cool air through said duct means and inner housing from outside the dryer housing, and to propel said air into said passage thereby providing a flow of cooling air over the fan bearings.

2. The invention as claimed in clairn 1 wherein said means for venting said passage comprises a duct means connected therewith opening outside said dryer housing'.

j 3. The invention as claimed in claim 1 wherein said means for venting said passage comprises means opening into the drying chamber.

4. The invention yas claimed in claim 3 wherein said means for venting said passage includes means opening i into the drying lchamber on'the suction side of the fan.

5. In a drum type dryer including a housing enclosing a drying chamber, a perforated drum rotatably disposed within the drying chamber, an axial fan mounted within the drum for circulation of air therethrough, said fan including a drive shaft, bearings journaling said drive shaft, and a hub secured to an end of said drive sha-ft having fan blades extending radially therefrom, means for driving said fan in rotation, and :means for heating the air circulated within the drying chamber, the improvement for cooling the bearings of the fan comprising means within the drying chamber enclosing the fan bearings, said latter means including a cylindrical inner housing concentric with the drive shaft, and an inlet duct opening outside the dryer housing connected with la first end of said inner housing, an impeller on the drive shaft betweenV the opposite end of said inner housing and thehub, the hub extending in spaced concentric, relation around part of said inner housing to lform an annular passage therebetween, a cylindrical cowling secured in spaced concentric relation around said inner housing between said hub and said first end of said inner housing,

said cowling continuing said annular passage along the llength of said inner housing, and means for venting said housing through said inlet duct and inner housing, and Y to propel the air into said annular passage thereby providing a fiow of cooling air over the fan bearings.

6. The invention as claimed in claim 5 wherein said means for venting said annular passage comprises a duct means connected therewith opening outside said dryer housing, said duct means connected with said passage adjacent the first endof said inner housing.

7. The invention as claimed in claim 5 wherein said means for venting said annular passage comprises means opening into the drying chamber.

8. The invention as claimed in claim 7 wherein said means for Venting said annular passage includes a slot between the hub and said Cowling opening into the drying chamber on the suction side of the fan,

9. In a drum type dryer including a housing enclosing a drying chamber, a perforated drum rotatably disposed within the drying chamber, an axial fan mounted within the drum for circulation of air therethrough, said fan including a drive shaft, bearings journaling said drive shaft, and a hub-secured to an end of said drive shaft having yfan blades extending radially therefrom, a fan motor mounted outside the housing, belt means operatively connecting the motor and the drive shaft for driving said fan in rotation, and means for heating the air circulated within the drying chamber, the improvement for cooling the bearings of the fan and the belt means comprising means Vwithin the drying chamber enclosing the fan bearings, said latter means including an inner housing, and duct means opening outside the dryer housing connected with said inner housing, the belt means within the dryer housing being enclosed within said duct means, an impeller on the drive shaft between said inner housing and the hub, said hub extending in spaced relation around part of said inner housing to form a passage therebetween, and means fo-r venting said passage, said impeller being adapted during rotation of the fan to draw cool air through said duct means and inner housing from outside the dryer housing, and to propel said air into said passage thereby providing a flow of cooling air over the belt means and the `fan bearings.

10. The inven-tion as claimed in clai-m 9 wherein said means for Venting said passage comprises a duct means connected therewith opening outside said dryer housing.

11. The invention as claimed in claim 9 wherein said ymeans for venting said passage comprises means opening into the drying chamber.

12. The invention as claimed in claim 9 wherein said means for venting said passage includes means opening into the drying chamber on the suction side of the fan.

13. In a drum type dryer including a housing enclosing a drying chamber, a perforated drum rotatably disposed within the drying chamber, an axial fan mounted within the drum for circulation of air therethrough, said fan including a drive shaft, bearings journaling said drive shaft, and a hub secured to an end of said drive shaft having fan blades extending radially therefrom, a fan motor mounted outside the housing, belt means operatively connecting the motor and the drive shaft for driving said fan in rotation, Vand means for heating the air circulated within the drying chamber, the improvement for cooling the belt means and the bearings of the fan comprising means within the drying chamber enclosing the fan bearings, said latter means including a cylindrical inner housing concentric with the drive shaft, and an inlet duct opening outside the dryer housing connected with a first end 4of said inner housing, the drive shaft extending into said inlet duct, the belt means operatively connecting the motor and the drive shaft passing through said inlet duct, an impeller on the drive shaft between the opposite end of said inner housing and the hub, the

hub extending in spaced concentric relation around part of said inner housing to form an annular passage therebetween, a cylindrical Cowling secured in spaced concentric relation around said inner housing between said hub and said rst end of said inner housing, said cowling continuing said annular passage along the length of said inner housing, and means for venting said annular passage, said impeller being adapted during rotation of the fan to draw cool air from outside the dlyer housing through said inlet duct and inner housing and to propel the air into said annular passage thereby providing a iiow of cooling air over the belt means and the fan bearings.

14. The invention as claimed in claim 13 wherein said means for Venting said passage comprises a duct means connected therewith opening outside said dryer housing.

15. The invention as claimed in claim 13 wherein said means for venting said passage .comprises means opening into the drying chamber.

5 16. The invention as claimed in claim 13 wherein said means for venting said passage includes a slot between the hub and said Cowling opening into the drying chamber on the suction side of the fan.

References Cited by the Examiner UNITED STATES PATENTS 83,690 11/1868 Chambers 34-115 1,377,793 5/1921 Schwartz 34-115 xV 10 3,196,555 7/1965 Friedel et a1 34`115 FOREIGN PATENTS 969,238 9/1964 Great Britain.

15 FREDERICK L. MATrEsoN, JR., Primm-y Examiner.

C. R. REMKEAssz'sant Examiner. 

1. IN A DRUM TYPE DRYER INCLUDING A HOUSING ENCLOSING A DRYING CHAMBER, A PERFORATED DRUM ROTATABLY DISPOSED WITHIN THE DRYING CHAMBER, AN AXIAL FAN MOUNTED WITHIN THE DRUM FOR CIRCULATION OF AIR THERETHROUGH, SAID FAN INCLUDING A DRIVE SHAFT, BEARINGS SUPPORTING SAID DRIVE SHAFT, AND A HUB SECURED TO AN END OF SAID DRIVE SHAFT HAVING FAN BLADES EXTENDING RADIALLY THEREFROM, MEANS FOR DRIVING SAID FAN IN ROTATION, AND MEANS FOR HEATING THE AIR CIRCULATED WITHIN THE DRYING CHAMBER, THE IMPROVEMENT FOR COOLING THE BEARINGS OF THE FAN COMPRISING MEANS WITHIN THE DRYING CHAMBER ENCLOSING THE FAN BEARINGS, SAID LATTER MEANS INCLUDING AN INNER HOUSING, AND DUCT MEANS OPENING OUTSIDE THE DRYER HOUSING CONNECTED WITH SAID INNER HOUSING, AN IMPELLER ON THE DRIVE SHAFT BETWEEN SAID INNER HOUSING AND THE HUB, SAID HUB EXTENDING IN SPACED RELATION AROUND PART OF SAID INNER HOUSING TO FORM A PASSAGE THEREBETWEEN, AND MEANS FOR VENTING SAID PASSAGE, SAID IMPELLER BEING ADAPTED DURING ROTATION OF THE FAN TO DRAW COOL AIR THROUGH SAID DUCT MEANS AND INNER HOUSING FROM OUTSIDE THE DRYER HOUSING, AND TO PROPEL SAID AIR INTO SAID PASSAGE THEREBY PROVIDING A FLOW OF COOLING AIR OVER THE FAN BEARINGS. 